1. Field of the Invention
The present invention relates to a power supply system, and specifically to a power supply system that assures reliability in power supply even when an abnormality occurs in a power system from which power is being received.
The power system or power grid, here, includes the power supply supplied from the plant and the distributed power system i.e. micro power grid.
2. Description of the Prior Art
Participation to the power trading business has also become possible without restrictions. An increasing number of users are installing fuel cells and photovoltaic power generating facilities at their sites. An abnormality may occur due to a disaster in, for example, a power system from which a user usually receives power. When a plurality of power supplies are distributed as described above, if the user can switch the power system to another normal power system and receive power, the reliability of power supply to the user can be improved.
Japanese Patent Laid-open No. 2005-151730 proposes a propriety determination method by which an optimum energy source is selected in consideration of a running cost and environmental loads, such as Sox and Nox when a new energy source is installed. In this document, however, there is no description concerning countermeasures that should be taken when an abnormality occurs in a power system from which power is usually received.